Full spectrum boosts solar cell power

Abstract

Solar cell efficiency, currently hovering in the 15 to 20 percent range, can theoretically be boosted to as high as 70 percent by printing specially engineered nanostructures on the cells, researchers say. Conversion efficiency of solar cells has long been thought limited to 34 percent for a single material or less than about 45 percent for the most efficient cells. A thermodynamic limit is responsible for this practical impediment. The conversion process of solar cells is typically not very efficient: A conventional silicon solar cell commercially available today converts only 15 to 20 percent of the energy of the sunlight to electricity, with the balance lost as heat. Blue and green lightwaves are converted to electricity with an efficiency of less than 50 percent, while infrared light is not absorbed by a silicon solar cell at all. The highest efficiency record realized by a silicon solar cell was 27 percent.